The Discovery of G Proteins

Martin Rodbell and his collaborators found that a
transducer provided the link between the hormone
receptor (the discriminator) and the amplifier. Alfred
G. Gilman and his co-workers used genetic and
biochemical techniques to identify and purify the G
protein. They used lymphoma cells that normally can be
activated by a receptor to form cyclic AMP.

Normal Lymphoma
Cell

A
mutated lymphoma cell was found to contain a normal
receptor and a normal cyclic AMP-generating enzyme but
was yet unable to respond because it lacked the
transducer.
This was a good system to assay purified G
proteins.

Mutated Lymphoma Cell

A G protein could
be isolated from normal brain tissue and inserted in
the mutated cell, thereby restoring its function.